Antimicrobial properties are the effects by which a material suppresses the growth of, or kills, microorganisms that come into contact with it, and they are reported as an inhibition zone, a minimum inhibitory concentration, or a reduction in viable count over a stated contact time. Oxide and metal nanoparticles dispersed in a polymer matrix act through several routes at once: release of metal ions, generation of reactive oxygen species, and direct contact with the cell envelope, so a hybrid of oxide nanoparticles in chitosan shows activity against both Gram-positive and Gram-negative strains [1]. For silver the released ion is the dominant agent, and the rate at which the particle dissolves oxidatively therefore controls how long the effect lasts [2]. Chitosan contributes its own polycationic action and, when combined with a plant extract, also carries antioxidant activity [3]. Bringing such particles into a food-contact film raises the question of how much silver migrates out of it [4]. Composite films of gelatin and chitosan nanoparticles extend the same approach to edible packaging [5].
Antimicrobial agents and applications·Organic Chemistry·Chemistry·Physical Sciences